/*
 * Copyright 2000-2016 JetBrains s.r.o.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.jetbrains.java.decompiler.struct.attr;

import java.io.DataInputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import org.jetbrains.java.decompiler.code.CodeConstants;
import org.jetbrains.java.decompiler.modules.decompiler.exps.AnnotationExprent;
import org.jetbrains.java.decompiler.modules.decompiler.exps.ConstExprent;
import org.jetbrains.java.decompiler.modules.decompiler.exps.Exprent;
import org.jetbrains.java.decompiler.modules.decompiler.exps.FieldExprent;
import org.jetbrains.java.decompiler.modules.decompiler.exps.NewExprent;
import org.jetbrains.java.decompiler.struct.consts.ConstantPool;
import org.jetbrains.java.decompiler.struct.consts.PrimitiveConstant;
import org.jetbrains.java.decompiler.struct.gen.FieldDescriptor;
import org.jetbrains.java.decompiler.struct.gen.VarType;

public class StructAnnotationAttribute extends StructGeneralAttribute {
  private List<AnnotationExprent> annotations;

  @Override
  public void initContent(ConstantPool pool) throws IOException {
    annotations = parseAnnotations(pool, stream());
  }

  public static List<AnnotationExprent> parseAnnotations(ConstantPool pool, DataInputStream data) throws IOException {
    int len = data.readUnsignedShort();
    if (len > 0) {
      List<AnnotationExprent> annotations = new ArrayList<>(len);
      for (int i = 0; i < len; i++) {
        annotations.add(parseAnnotation(data, pool));
      }
      return annotations;
    } else {
      return Collections.emptyList();
    }
  }

  public static AnnotationExprent parseAnnotation(DataInputStream data, ConstantPool pool) throws IOException {
    String className = pool.getPrimitiveConstant(data.readUnsignedShort()).getString();

    List<String> names;
    List<Exprent> values;
    int len = data.readUnsignedShort();
    if (len > 0) {
      names = new ArrayList<>(len);
      values = new ArrayList<>(len);
      for (int i = 0; i < len; i++) {
        names.add(pool.getPrimitiveConstant(data.readUnsignedShort()).getString());
        values.add(parseAnnotationElement(data, pool));
      }
    } else {
      names = Collections.emptyList();
      values = Collections.emptyList();
    }

    return new AnnotationExprent(new VarType(className).value, names, values);
  }

  public static Exprent parseAnnotationElement(DataInputStream data, ConstantPool pool) throws IOException {
    int tag = data.readUnsignedByte();

    switch (tag) {
    case 'e': // enum constant
      String className = pool.getPrimitiveConstant(data.readUnsignedShort()).getString();
      String constName = pool.getPrimitiveConstant(data.readUnsignedShort()).getString();
      FieldDescriptor descr = FieldDescriptor.parseDescriptor(className);
      return new FieldExprent(constName, descr.type.value, true, null, descr, null);

    case 'c': // class
      String descriptor = pool.getPrimitiveConstant(data.readUnsignedShort()).getString();
      VarType type = FieldDescriptor.parseDescriptor(descriptor).type;

      String value;
      switch (type.type) {
      case CodeConstants.TYPE_OBJECT:
        value = type.value;
        break;
      case CodeConstants.TYPE_BYTE:
        value = byte.class.getName();
        break;
      case CodeConstants.TYPE_CHAR:
        value = char.class.getName();
        break;
      case CodeConstants.TYPE_DOUBLE:
        value = double.class.getName();
        break;
      case CodeConstants.TYPE_FLOAT:
        value = float.class.getName();
        break;
      case CodeConstants.TYPE_INT:
        value = int.class.getName();
        break;
      case CodeConstants.TYPE_LONG:
        value = long.class.getName();
        break;
      case CodeConstants.TYPE_SHORT:
        value = short.class.getName();
        break;
      case CodeConstants.TYPE_BOOLEAN:
        value = boolean.class.getName();
        break;
      case CodeConstants.TYPE_VOID:
        value = void.class.getName();
        break;
      default:
        throw new RuntimeException("invalid class type: " + type.type);
      }
      return new ConstExprent(VarType.VARTYPE_CLASS, value, null);

    case '[': // array
      List<Exprent> elements = Collections.emptyList();
      int len = data.readUnsignedShort();
      if (len > 0) {
        elements = new ArrayList<>(len);
        for (int i = 0; i < len; i++) {
          elements.add(parseAnnotationElement(data, pool));
        }
      }

      VarType newType;
      if (elements.isEmpty()) {
        newType = new VarType(CodeConstants.TYPE_OBJECT, 1, "java/lang/Object");
      } else {
        VarType elementType = elements.get(0).getExprType();
        newType = new VarType(elementType.type, 1, elementType.value);
      }

      NewExprent newExpr = new NewExprent(newType, Collections.emptyList(), null);
      newExpr.setDirectArrayInit(true);
      newExpr.setLstArrayElements(elements);
      return newExpr;

    case '@': // annotation
      return parseAnnotation(data, pool);

    default:
      PrimitiveConstant cn = pool.getPrimitiveConstant(data.readUnsignedShort());
      switch (tag) {
      case 'B':
        return new ConstExprent(VarType.VARTYPE_BYTE, cn.value, null);
      case 'C':
        return new ConstExprent(VarType.VARTYPE_CHAR, cn.value, null);
      case 'D':
        return new ConstExprent(VarType.VARTYPE_DOUBLE, cn.value, null);
      case 'F':
        return new ConstExprent(VarType.VARTYPE_FLOAT, cn.value, null);
      case 'I':
        return new ConstExprent(VarType.VARTYPE_INT, cn.value, null);
      case 'J':
        return new ConstExprent(VarType.VARTYPE_LONG, cn.value, null);
      case 'S':
        return new ConstExprent(VarType.VARTYPE_SHORT, cn.value, null);
      case 'Z':
        return new ConstExprent(VarType.VARTYPE_BOOLEAN, cn.value, null);
      case 's':
        return new ConstExprent(VarType.VARTYPE_STRING, cn.value, null);
      default:
        throw new RuntimeException("invalid element type!");
      }
    }
  }

  public List<AnnotationExprent> getAnnotations() {
    return annotations;
  }
}